BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Blackburnian Warbler

ParulidaeForest birdsSetophaga fusca

Blackburnian Warbler has surged: up 109% on the route-weighted index since 1968.

+109%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
522RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Blackburnian Warbler

The Blackburnian Warbler (Setophaga fusca) is a North American member of the Wood-Warblers (Parulidae). In this analysis it is grouped with the forest birds.

Size
4.5–5.5 in long (11–14 cm) — a small, active songbird (typical for the family)
Habitat
Woodlands and forest edges, including wooded suburbs and parks.
Diet
Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
Range
Recorded on 522 Breeding Bird Survey routes across 20 states, most concentrated in the Appalachian Mountains.
Family
Parulidae · Forest birds

Notable Blackburnian Warbler TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Blackburnian Warbler has surged in surveyed states: up 109% on the route-weighted index since 1968.

Blackburnian Warbler Population Forecast

If the recent trend holds, Blackburnian Warbler is projected to rise about 21% by 2029 — from 0.28 in 2024 to a central estimate of 0.34 (95% range 0.27–0.42). A 5-year backtest shows a typical error of ±10.1%, with 100% of held-out values landing inside the 95% band.

+21%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.34Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.27–0.4295% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±10.1%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Blackburnian Warbler is projected to rise about 21% by 2029 — from 0.28 in 2024 to a central estimate of 0.34 (95% range 0.27–0.42). A 5-year backtest shows a typical error of ±10.1%, with 100% of held-out values landing inside the 95% band.19662029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.330.260.41
20260.340.260.41
20270.340.260.41
20280.340.270.41
20290.340.270.42

Where the Blackburnian Warbler Is Detected

BBS routes recording Blackburnian Warbler, sized by most recent count.

Blackburnian Warbler Population Trend by State

Blackburnian Warbler population trend by state.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Connecticut-9%197012
Georgiainsufficient datan/a2
Indianainsufficient datan/a1
Maine+65%196873
Maryland+198%19686
Massachusetts+208%196819
Michigan+485%196855
Minnesota+204%196937
New Hampshire+168%196825
New Jersey-3%19903
New York+72%196883
North Carolina+95%197416
Ohioinsufficient datan/a1
Pennsylvania+774%196876
Rhode Islandinsufficient datan/a2
Tennessee+763%19786
Vermont+400%196825
Virginia+174%196917
West Virginia14×197025
Wisconsin+168%196838

Blackburnian Warbler Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Blackburnian Warbler population trend by Bird Conservation Region.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Boreal Hardwood Transition+201%1968113
Lower Great Lakes / St. Lawrence Plain+295%196936
Atlantic Northern Forest+118%1968153
Prairie Hardwood Transition+2%197017
Appalachian Mountains+586%1968173
New England / Mid-Atlantic Coast+61%196927

Blackburnian Warbler Conservation Status

Our route-weighted index shows it up about 109% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.